Scaling Gain Compensation Method for Current Measurement of Motor Drive Applications Under Locked-Rotor Condition Considering Inequality of Each Phase Resistances

This paper presents a scaling gain compensation method for current measurement of motor drive application under locked-rotor condition. In several applications such as elevators, cranes and so on, initial commissioning processes are performed under locked-rotor condition. To compensate the current scaling gain errors, the proposed method performs d-q axis current control according to two-phase sensing methods in the stationary reference frame. Thereafter, the three-phase scaling gains are estimated using the d-axis current command and the output d-axis voltage, and then, compensated. The proposed algorithm considers the inequality of the phase resistances so that the compensation performance can be improved. The validity of the proposed algorithm was verified through experiments.